Producing films from polyethylene (“PE”) resins via melt blown film process (also know as bubble process) is generally known. In the melt blown process, bubble stability is an important factor because it restricts the film production rate. Furthermore, the bubble stability is directly related to melt strength (“MS”) of the resin.
It is also generally known that high pressure low density polyethylene (“LDPE”) inherently possesses a higher melt strength than linear polyethylene (“LPE”). Therefore, LDPE is particularly useful in blowing large diameter thick gauge bubbles.
LDPE production may be facilitated via different methods including, but not limited to, autoclave process or tubular process. Although autoclave LDPE resins may possess a high melt strength, films produced from such resins fail to exhibit the same level of toughness exhibited by the films produced from tubular LDPE resins having the same melt index (“MI”) as the autoclave LDPE resins. Furthermore, although the LDPE resin production via a tubular process, i.e. using a tubular reactor, can provide a higher ethylene conversion as compared to autoclave process; however, the melt index of a tubular resin must be significantly lowered compared to an autoclave resin in order to achieve the same melt strength as the autoclave resin; hence, this may consequently affect the production rate negatively.
European Patent Publication No. 0 069 806 A1 discloses a process for producing polyethylene having constant physical and chemical properties.
U.S. Provisional Application No. 60/624,434 discloses a process for producing low density polyethylene compositions and polymers produced therefrom.
Despite the research efforts in developing and improving resins of high melt strength, there is still a need for a resin of high melt strength suitable for high throughput film production.